Moldboard supporting structure

ABSTRACT

A torsion spring is arranged coaxial with the pivotal mounting of the snowplow moldboard. One end of the spring is fixed to the moldboard supporting frame. The opposite free end of the spring acts against the moldboard assembly below the pivotal mounting thereof to yieldingly restrain movement of the moldboard assembly about its pivot in the event the blade of the moldboard strikes a fixed object.

United States Patent Inventors Thomas M. Bogenschutz Clayton; Eugene A. Farrell, Evans Mills, both 01, N.Y.

Appl. No, 868,325

Filed Oct. 22, 1969 Patented Sept. 14,1971 Assignee Compro-Frlnk Corporation Clayton, N.Y.

MOLDBOARD SUPPORTING STRUCTURE 2 Claims, 3 Drawing Figs.

US. Cl 37/42 VL, 172/265, 172/711, 172/794 Int. Cl E0111 5/04, A0 1 b 61/04 Field of Search 172/261,

[ 5 6] References Cited UNITED STATES PATENTS 2,136,851 11/1938 Jess 172/711 X 2,312,405 3/1943 Haagen 172/264 2,697,289 12/1954 Standfuss 37/53 X 3,041,753 7/1962 Koloset is 172/711 x FOREIGN PATENTS 293,648 12/1953 Switzerland Primary Examiner-Robert E. Pulfrey Assistant Examiner-R. E. Suter Altorney-D. Emmett Thompson ABSTRACT: A torsion spring is arranged coaxial with the pivotal mounting of the snowplow moldboard. One end of the spring is fixed to the moldboard supporting frame. The 0pposite free end of the spring acts against the moldboard assembly below the pivotal mounting thereof to yieldingly restrain movement of the moldboard assembly about its pivot in the event the blade of the moldboard strikes a fixed object.

PATENTEIJ SEP] 41% INVENTORS. THOMAS M. BUEENSUIUTZ. BY EUGENE A. FARRELL.

ATTURNEY.

MOLDBOARD SUPPORTING STRUCTURE BACKGROUND OF THE INVENTION Material-moving structures of the type embodying a moldboard assembly including a moldboard and a scraper blade mounted on a powered vehicle have conventionally included a trip mechanism. In such devices, the moldboard is mounted on its supporting frame for pivotal movement about a horizontal axis, and the trip mechanism includes spring means to yieldingly resist pivotal movement of the moldboard assembly in the event the blade on the moldboard strikes a fixed object. The springs in the trip mechanism yieldingly maintain the moldboard assembly in operative position.

Such trip mechanism include linkage in conjunction with helical compression, or tension, springs. The linkage is connected to the moldboard intermediate the pivotal mounting thereof and the top edge of the moldboard. This construction involves several parts and is costly to produce. Also, the force that is generated by the moldboard striking a fixed object is transmitted through the moldboard sheet and ribs to the point here the linkage is attached thereto. This creates a torsional load or twisting effect in the moldboard, with the result that metal fatigue is developed especially in the area of wells and the moldboard eventually fractures.

This invention has as an object a moldboard supporting structure for snowplows and the like, wherein only a torsion spring, or a pair of torsion springs, are arranged coaxial with the pivot on which the moldboard assembly is mounted, eliminating the use of links, arms, toggles, etc., with a corresponding reduction in the cost of manufacturing and assembling the snowplow BRIEF and improving the operation of the moldboard assembly.

BRIEF SUMMARY OF THE INVENTION A torsion spring, or preferably a pair of torsion springs are arranged coaxial with the pivot about which the moldboard assembly molds when the forward motion of the moldboard blade is stopped by engagement with a fixed object. Preferably, a pair of torsion springs are employed and they are mounted on rods forming the pintles supporting the moldboard assembly.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a top plan view of a snowplow structure embodying our invention.

FIG. 2 is a view taken on line 2-2, FIG. 1.

FIG. 3 is a view, similar to FIG. 2, illustrating the blade encountering a fixed object.

DETAILED DESCRIPTION The snowplow structure disclosed consists of a drive or push frame formed with converging members fixed to a crossmember 11. The base member 11 is provided with rearwardly extending ears or brackets 12 apertured to receive a pivot pin by which the drive frame is pivotally mounted to the front end of a motor vehicle.

The blade assembly is mounted on a supporting frame which includes a crossmember l3 pivotally mounted intermediate its end, as at 15, to the forward end of the push frame members 10. Braces l7 converge rearwardly from the ends of the beam 13 and are fixedly secured, as by welding, to a gear quadrant 20. A power-operated worm gear 21 is mounted on the push frame and meshes with the quadrant to swing the supporting frame about the pivot 15. Skid shoes 22 are mounted at the ends of the beam 13 for supporting the same. The general arrangement of this structure is disclosed in US. Pat. No. 3,464,129, to Thomas M. Bogenschultz, Sept. 2, I969.

The moldboard assembly consists of a metallic sheet 23 fixedly secured, as by welding, to curved ribs 25. A transversely extending angle member 27 is fixed to the lower ends of the ribs 25, and a blade member 30 is fixedly secured to the angle member 27, and to the moldboard sheet 23.

The beam 13 is provided with forwardly extending brackets 31. There are two pairs of these brackets arranged in spacedapart relation on the beam 13. Brackets 33 of each pair are attached to the beam 13 in brackets central portion thereof. The other brackets 35 of each pair are fixed to the beam adjacent the outer ends thereof. The moldboard assembly is formed with a pair of the ribs 25 in the central portion thereof, and with pairs of the ribs 25 spaced outwardly from the ribs 25 at the center of the moldboard assembly, these latter ribs being spaced complemental to the spacing of the brackets 35 fixed to the beam 13. The inner ribs 25 are located complemental to the inner brackets 33 carried by the beam 13. The ribs 25 on the moldboard assembly serve as rearwardly extending brackets and they, and also the brackets 33, 35, are apertured to receive pivot pins 40,41. With this arrangement, the moldboard assembly may move pivotally about the rods 40, 41, in a clockwise direction in the event that the blade member 30 encounters a fixed object, as indicated at 42, FIG. 3, during forward movement of the snowplow.

A torsion spring 50 is mounted on each of the rods 40, 41. The inner ends of these springs are fixed to the beam 13, as by U bolts 51. The opposite ends 53 of the springs act against the lower portion of the moldboard assembly, including a reinforcing plate 55 welded to the rear side of the moldboard sheet 23 and the angle member 27.

It will be apparent that the springs 50 function to yieldingly urge the lower edge portion of the moldboard assembly forwardly. The extent of this forward movement is limited by stop rods 57, pivotally joined, as at 60, to the moldboard ribs 25. These rods 57 extend through a bracket 61 forming a part of the beam structure 13. The rear ends of the rods 57 are threaded to receive adjusting nuts 63. A yieldable member 65, such as a rubber sleeve, is interposed between the member M and the nuts 63. By adjusting the nuts 63, the forward position of the blade 30 becomes fixed. Upon the blade 30 encountering a fixed object, as indicated at 42, FIG. 3, it and the lower portion of the moldboard is moved rearwardly about the pivot pins 40, 41, against the action of the springs 50.

Brackets 33, fixed to the central portion of the beam 13, are employed, in conjunction with the centrally located ribs 25 on the moldboard, to provide a more rigid supporting structure for the moldboard assembly, and also to make provision for the pair of the springs 50 having their outer end portions 53 acting against the moldboard assembly, at points spaced a considerable distance from the pivot pin 15, to afford greater stability to the moldboard assembly during the tripping action thereof.

It will be apparent that this torsion spring arrangement eliminates the complicated linkage structures now in current use, reducing the manufacturing cost of the snowplow to a considerable extent. It also permits the mounting brackets for the moldboard assembly to be kept to minimum length so that the forces are transmitted through the structural members of the moldboard, including the blade 30 and backer angle 27.

With this torsion spring design, the moldboard sheet 23 encounters substantially no force other than the snow load in plowing. With compression and tension spring trips heretofore used, with the accompanying linkage which is attached to the moldboard a considerable distance above the pivot point, usually at least midway between the lower and upper edges of the moldboard, the force that is generated by striking an object is transmitted through the moldboard sheet and ribs to the point where the linkage is attached. This creates a torsional load, that is, a twisting effect in the moldboard, with the result that metal fatigue and failure results. Furthermore, this torsion spring construction leaves the central portion of the drive frame entirely clear to mount a lifting bar in that area, which compensates for center of gravity change when the plow is elevated when in an angled position, whereby the tilting edge of the moldboard can be raised to give adequate ground clearance.

As will be understood by those familiar with this art, the torsion springs 50 must be capable of exerting a very substantial force against the lower portion of the moldboard assembly.

This necessitates these springs being formed from tempered spring steel rod of substantial cross-sectional dimension, being about 1% inches of diameter for an average highway plow. This means that when the springs are wound into the tight helical coil, the wound springs have an internal diameter of sub stantial dimension, exceeding the diameter of the pivot rods 40, 41. Accordingly, a sleeve 67 is positioned on each of the pivot rods to maintain the springs 50 in concentric relation therewith.

What we claim is:

1. A moldboard assembly supporting structure for snowplows and the like comprising a support frame having a crossbeam, a moldboard assembly pivotally mounted near the lower edge thereof directly to said beam on an axis extending parallel thereto, a pair of torsion springs arranged along said axis, the inner ends of said springs being fixed to said beam, the opposite free ends of said springs engaging the rear side of said moldboard assembly in areas below said axis, and spaced outwardly from said inner ends said springs being operable to yieldingly urge the lower edge of said moldboard assembly forwardly from said beam, and stop rods attached at like ends to said moldboard assembly below said pivotal axis in areas contiguous to the engagement of the opposite free ends of said springs with said moldboard assembly, said rods extending rearwardly from said moldboard assembly siidably through said beam structure, means carried at opposite end portions of said rods and adjustable therealong for engagement with said beam structure to limit forward movement of the lower edge of said assembly by said springs.

2. A structure as set forth in claim 1, wherein said beam is provided with spaced-apart forwardly extending brackets, said moldboard assembly is provided with rearwardly extending brackets, a pivot rod extending through said brackets, and said torsion spring being mounted on said pivot rod. 

1. A moldboard assembly supporting structure for snowplows and the like comprising a support frame having a crossbeam, a moldboard assembly pivotally mounted near the lower edge thereof directly to said beam on an axis extending parallel thereto, a pair of torsion springs arranged along said axis, the inner ends of said springs being fixed to said beam, the opposite free ends of said springs engaging the rear side of said moldboard assembly in areas below said axis, and spaced outwardly from said inner ends said springs being operable to yieldingly urge the lower edge of said moldboard assembly forwardly from said beam, and stop rods attached at like ends to said moldboard assembly below said pivotal axis in areas contiguous to the engagement of the opposite free ends of said springs with said moldboard assembly, said rods extending rearwardly from said moldboard assembly slidably through said beam structure, means carried at opposite end portions of said rods and adjustable therealong for engagement with said beam structure to limit forward movement of the lower edge of said assembly by said springs.
 2. A structure as set forth in claim 1, wherein said beam is provided with spaced-apart forwardly extending brackets, said moldboard assembly is provided with rearwardly extending brackets, a pivot rod extending through said brackets, and said torsion spring being mounted on said pivot rod. 